KlarSnow

Ok, so his MPRF should be switching in order to minimize these issues... again you are agreeing that it shouldn't be a static single PRF that never changes. which is what Maestro has claimed is the only solution. This is my issue with his description, he has set a static MPRF PRF, and is not simulating any kind of adaptive adjusting or switching in order to help any of these situations, if he did that, it would resolve many of these issues, Oh no I have A SnR issue or eclipsing issue at this particular PRF, so swap to the next one that doesn't have that, and keep doing that all the way in to the edges of the MLC, which again, will be smaller compared to HPRF because the clutter zones are more spread out due to harmonics. Again this is all covered in that MPRF PRF paper I posted earlier, it discusses how different PRF's have varying levels of clutter issues and eclipsing, and how swapping between them can allow you to track through one PRF's issues. He didn't even engage with that part of the paper, just dismissed it out of hand while pointing at the setup to the problem as proving his point. I also very much do not understand the point of modelling all of this stuff with the radar in utterly minute detail which adds and adds to the development time and opens up so many issues with starting assumptions, how does all of this stuff work with chaff, how does all of this stuff work with jamming. There should be an end goal for the system, that quite honestly can be abstracted, it feels very much like there is no end goal, and we are iterating for years at this point with no real end goal for how the missile should work in sight, and constantly varying levels of missile effectiveness and needlessly obfuscated mechanics. This compounds with every other system and missile that is in some varying state of needing an overhaul. The Russian missiles should have a lot of this complexity and should not be nearly as susceptible to all of this as well, but they are stuck on the old missile API until this one is "done". The Aim-54 should have a lot more complexity to it but my understanding is Heatblur cant do anything more complex than currently because this guidance API isn't "done". I get that all of this takes time, but it has been over 3 years since ED has started reworking this stuff and they have been bouncing back and forth between various things and have not clearly explained what exactly the end goal of what we should see looks like. This combined with what appears to be some very questionable assumptions about how radars in general work (this applies to far more than the amraam) leads to a very general feeling of disconnect between the community and the developers. This is a game, what is the desired endstate of gameplay that you are working towards, this drives all of your assumptions about how these things you are speculating on work. What are you trying to make here? What is the criteria of done? It is obviously working as intended as he has explained, but is that how its going to sit? is the next update going to break it more, are any of the possible solutions we are talking about or theories going to eventually be implemented? Basically what this entire development of various features on the AMRAAM feels like is pointless iteration that either has no discernable or in many cases a deleterious effect on the gameplay. A "Feature" is added, the community points out the problems, an iteration on it occurs, the community points out more issues, nobody knows what the desired endstate is, and this cycle continues with features getting added or removed or tweaked and nobody has a definition of what "realistic" results for this stuff should be. This has extended and extended this process and lead to whiplashes back and forth on the capability of weapons and the effectiveness of various parts of how the gameplay works. How is this all supposed to work in the end? If we knew that we could appropriately assess bugs vs not implemented yet vs working as intended. Right now there is no clear layout of how all of this works.

But using a single PRF then means you have a massive clutter and ambiguity problem exactly as described, that excellent SnR from a single PRF would be great, for long range look up, not for a missile that is always trying to loft and acquire at relatively short ranges in lookdown, and is designed to engage low altitude targets like cruise missiles. He has developed a system that cannot resolve targets in the typical engagement geometries, and has no clutter reduction capabilities. So of course it is going to have a lot of problems. Multiple PRF's also reduces the size of the notch in MPRF, making it much smaller than in HPRF, again this adds to all of the guidance and autopilot stuff, if the notch in MPRF was say only 30 knots wide, instead of 100 knots wide, that massively simplifies the notch reacquisition problem.

Then I bring it back to the points raised earlier, there are many many methods for reacquiring and dealing with momentary loss of track that have to do with the autopilot, and as has been discussed in here, he is using a single PRF MPRF which is functionally worthless, you can't sort anything out of the ambiguities with that, so the doppler notch will be massive, the clutter problems will be massive. I'm sorry but saying you are developing a single PRF MPRF and then dismissing all research that shows that multiple PRF MPRF resolves many range and clutter ambiguities, implies a massive lack of understanding of what is going on here. The missile should not completely lose guidance and go utterly dumb when the target enters the notch, and Signal to Noise ratio still plays a part. Using MPRF spreads the clutter signal through all of the range bins. The notch still exists but again, if you are close enough, it can still see the target because the amplitude is high enough. My issue right now is less the range gating vs clutter issue, its more the assumptions that are going into this "advanced missile API" and the follow on effects because they betray an utter misunderstanding of what should be some very basic MPRF concepts. My other issue is that the dev working on this is not engaging with any of the research, he is dismissing it and literally cherry picking the setup that is describing the problems in the first part of the paper and then ignoring the solution provided at the end because he has "seen it all before". The target diving through the notch should not be an unexpected event for a missile that operates with a pulse doppler radar. It should be an expected event that the missile has countermeasures for, many of them being discussed here that minimize or allow it to reacquire after the notch. The way it is right now the missile is completely defeated by a maneuver that is easily predictable, and quite easily resolved. We are basically pretending that the missile is developed solely for clear air look up employment, that is the only way these design decisions make any sense.

A paper that explicitly says the opposite, and has data later on to back up why (seeker accuracy and SnR at close range is better than supporting radars,especially in a degraded environment) and as GGTharos said there are ample manuals that match this paper as well. How old are your documents. https://trace.tennessee.edu/cgi/viewcontent.cgi?article=6680&context=utk_gradthes

No they wont because they are range bins... why would they have any of the main lobe ground return in them. IF they are sorted by range and in the situation presented at the start of this thread. There is no Main Lobe or side lobe clutter in the 2.5 Nautical mile range bin. So if you sort it by range and receive the unambiguous range benefits of MPRF with PRF Jitter, how is the Main lobe or side lobe doppler that is 20 miles away getting into the 2.5 nautical mile range bin. And if it is, how is it of such magnitude that it is overwhelming the target return. None of this is happening on a single pulse.... This is all integrated over several pulses on several PRF's MPRF Radars sort by Range bins and track by Range bins first, then they see if the doppler return is in there. Thats what the range vs doppler matrix is. If you have them all laid out again, why if there is no ground return coincident with target range, would any of the ground clutter be in the same range bin as the target. The side of this as well is that by sorting the entire return into range bins the total clutter level in each bin is lowered. Think instead of the massive MLC spike you get in HPRF, you instead have as many little MLC spikes as you have range and velocity bins. Makes it much much easier to see the target which will have all of its return in one bin, vs the entire spread out clutter spectrum. If you are doing a single PRF MPRF radar as is apparently being implemented, then yeah, none of this works because you cant solve any of the ambiguity problems and there will totally be doppler in every single range bin no matter what you do.

And why would it assume Unambiguous range if it couldn't get unambiguous range using MPRF... This is the baseline assumption everyone in this conversation besides yourself is starting from. That matrix on the side looks an awful lot like the MPRF range vs doppler matrix in the video that Krippz posted. I wonder if those are linked. Did you read to the end where he runs the simulation with the varying PRF's and determines that he can detect targets out to 23NM in lookdown? He definitively shows that using all of these values and yes he calculates the ground clutter using the same method you did. And yet doing all of that he reaches the conclusion that his theoretical radar with optimized PRF jitter can detect targets in that situation out to 23 NM... I guess I'll add that all of these are assuming a good level of sidelobe cancelling, this is an important part of MPRF, and helps a lot with the clutter problems. I'll ask you this, you keep saying what clutter, the papers and all of these theories and that patent are telling you they dont have problems with any of it by using these methods. So what clutter are you talking about that is magically still there after applying these methods? The mainlobe? The sidelobes? They are running these calculations and doing the PRF Jitter/Switching regardless and it resolves the range ambiguity regardless of clutter.

Another paper from 1989 directly describing this https://apps.dtic.mil/sti/pdfs/ADA220735.pdf

Keep reading there is a lot more pages to that Page 81, that's his conclusion on what a 10Khz PRF jittered radar could see at 9000 feet just by randomly picking PRF's, not even optimizing it, just randomizing it. And Page 88 shows that by optimizing it at 9000 feet above the ground his theoretical 10Khz MPRF radar can detect targets out to 23 nautical miles in clutter. And this is according to Nighthawk and others the bad way of doing this that reduces your detection range. PRF switching as they said should be even better... To be honest this isn't even the best paper about this, it just was one of the first to pop up, and it is fairly easy to understand.

Not trying to imply anything, just honestly quite curious as to why these things have been prioritized and then implemented in an apparently nonfunctional manner, I quite honestly think this entire conversation has been quite constructive, because it at least has shown exactly where the disconnect between your community and at least one of your staff is regarding how radars work. I apologize if my incredulity came off harsh. This should be really easy. The paper I just posted describes exactly what maestro is saying is impossible, somebody at ED read it please. There are many many like it and they are not hard to find.

Why not, this paper seems to think you can do exactly what you are saying it cannot. As does just about any other you go and look at, where is your source that extended clutter prevents MPRF from resolving targets. Because every source I, and everyone here but apparently you has seen, says exactly the opposite. Every source on MPRF says MPRF has range and velocity ambiguity, but with techniques like PRF jitter and various processing techniques it is the most reliable method of tracking targets at all aspects in lookdown. MPRF is specifically chosen to help with sidelobe and main lobe clutter because it reduces the amplitude in the range cells https://calhoun.nps.edu/handle/10945/5544 What exactly is the reason this does not work? And seriously it takes 30 seconds to google a research paper that is explicitly saying your claim is incorrect. This is why everyone is getting so utterly frustrated with how this guidance and radar stuff is going. There are blatantly clear sources that say how this works and whoever is designing these projects appear to be explicitly avoiding any of these for some unknown reason.

You should easily be able to get to .1 NM with an MPRF radar for range ambiguity. Multiple miles of range ambiguity is a characteristic of HPRF radars, not MPRF ones. Unless you are saying the radar isnt using a PRF jitter in order to solve the range ambiguity problem, which is what.....every MPRF radar does. Ok, so what I have gathered is you are simulating a single PRF MPRF seeker, which at first glance exactly as you have depicted here....is functionally useless. Which is why EVERY FUNCTIONAL VERSION OF MPRF in use.... uses a PRF jitter in order to give it very accurate range and velocity measurement with no ambiguity. you can find many MANY papers on this and how this works, and this is what everyone has assumed you are implementing when you say MPRF. So yeah again, working as intended, but not realistic for any MPRF radar that I'm aware of in a military context. My question now, is why did you implement a useless range gating feature on a radar that cannot exploit it? Should you not have researched and added MPRF Jitter first? Have you researched this type of radar at all? Because to me it looks like you are running through the entire timeline of radar research in the 1960's and 70's where scientists around the world figured this out. Instead of using the ample resources that are available online that tell you how this all works.

So you are saying you are range gating with HPRF yeah of course that isn't going to work at all if your Range ambiguity is as large as your seekers detection range. What exactly is the point of that feature then. Also HPRF seekers start to have good range ambiguity at very close ranges, once you get close enough that you are receiving returns before the next pulse goes out. it should be quite possible to have good range ambiguity at 2-3 miles with an HPRF X band seeker. Range gating with HPRF is completely pointless so if this was known why did you implement it like this. And why is this not using MPRF which does not have any of this issue. Regarding the INS..... your telling me it has to exactly match the predicted INS cue, the INS cue doesn't have error bars based on last prediction and how long its been since it saw it, it just says straight line and gives up even if it sees another target magically appear out of the notch? And that also doesnt hold up with why all the missiles pitched UP when the target went into the notch, if they had any kind of predictive tracking through their INS, the last they saw the target was going DOWN before it entered the notch, so they should have at lost track pitched DOWN towards their last cue not UP. Here is the last instant before the notch. I've circled roughly where the missiles should think the target is going. Upon loss of track should they not point at that point and look for the target again? Instead They start to pull up away from that intercept point the instant they get notched. It also cant predict a turn? The target was turning towards MLC, THE MOST DOMINANT THING in the doppler spectrum (especially in HPRF) that has been known about since we started operating with pulse doppler radars, and it has zero logic to go..... maybe the target will come out of the notch in a moment, and it was turning? This is all before I point out that the F-16 turned its belly to the missile revealing the massive RCS (compared to its nose or even side on profile) of its wings, and tail surfaces perpendicular to the missiles seeker. So it should have seen an absolutely massive amplitude spike even though yes there is all that ground clutter. There is a lot of ground clutter but the ground clutter is diffuse, and not nearly as reflective as the metal F-16 directly in front of it. The target return from that RCS that is at 2-3 miles that just flashed a reflective billboard at the missile isn't enough to keep it visible above main lobe clutter which while large is also 22 miles away down the direct line of sight. You are also assuming that the radar once in track isn't angle gating the target and ignoring all returns that aren't within a very narrow window around the target.... precisely to mitigate this kind of issue and increase SnR. Finally this entire lookdown happens over water. Unless you are modelling a severe sea state, water has nowhere near the direct clutter return that land does, most of the energy in this scenario is reflected off the surface long of the target, yes some will still be coming back, but not nearly as much. So yeah for what you've implemented working as intended I guess, but I question why range gating was implemented on a radar (or mode of the radar) that it is apparently useless on, and there are so very many other things that a computerized missile of this sort can do to combat this. The notch is a known feature of working with Pulse doppler radars and has been for over 60 years, that a very modern missile as you have implemented it has zero effective countermeasures against it seems rather wrong. Now if you were to make this in MPRF, that's a completely different discussion, and is what everyone was assuming.

GGTharos, as always DTIC has a paper for that. https://apps.dtic.mil/sti/pdfs/ADA213452.pdf from 1987 and very illuminating on miss distance and what factors affect what. Key note relating to glint…. So 8 foot miss expected inherent to glint alone on a 32 foot wide (or long object) and yes this is why all of these shots were taken against a maneuvering target. Glint should not be much of a factor on steady state targets. Maneuvering targets are where glint can start to become more of an issue.

Im 100% aware of the complexity of the actuality of this, but this is perfectly demonstrative of the theory of what is happening.

Like this for those who arent visualizing the concept well... Vs something like this null

Since Glint effects on missile seekers was added to guidance a couple of years ago, there has been a drastic increase in missiles (AIM-7's in particular) just missing their targets for no reason other than glint. This has compounded with the effects of chaff, jamming and the notch to make sparrows of all varieties have a particularly terrible success rate, even when fired with good parameters and doing everything possible to help the missile they still have a very poor success rate. What is the desired rate of missing implemented by missile glint? I don't know what the implementation goal for this "feature" was, but I can attempt to derive what its actual effect in game is. It is very hard to specifically quantify because there are so many factors that lead to misses, but I have done the best I can. My methodology was take a Hornet vs a veteran Mig-21Bis, remove Chaff and flare from the Fishbed. Set the Fishbed to never use Chaff and Flare, and never use ECM. Both start at 20,000 feet 45 Nautical miles apart. In the hornet I immediately select max AB and accelerate towards the Fishbed straight on, at 16.0 NM I fire one AIM-7M with a loft, and then at 15.0 NM I fire a second one without a loft. Upon second missile away, I immediately dive at a 30-40 degree angle to get underneath the Fishbed to prevent any notch or drop lock behavior while it maneuvers. In all cases where the bandit does not drag and the missiles themselves did not get notched the missiles guided to a terminal intercept with plenty of energy left to guide to within fuzing distance. After 24 shots that I have good tracks of(many more since I disregarded all attempts where the Fishbed turned completely cold and kinematically defeated my missiles) 21 of those missiles made it to a terminal intercept successfully the 3 that I am not counting were: 1 was notched at long range, 1 was out dragged in the vertical, and the final one I'm not sure what happened but it didn't get close enough to have a chance. A successful result (no glint) was both missiles fuzing on the target, lock was held after first missile impact and on multiple shots you can see the second missile impacting the wreckage after the first. Overall results: Of 21 missiles that successfully terminated with the target, 6 missed for no discernable reason. These I can only chalk up to glint causing a random guidance miss. That is a success rate assuming everything works out perfectly of 71%. With a better than 1/4 odds that an AIM-7M will just randomly miss its target, without chaff, without a notch, and with energy to maneuver. This is the second time I had run through this methodology, the first time half of my tracks didn't save correctly so I did it all again, the first time through out of 20 missiles, 10 completely whiffed. Combining the 2 sets of data that's 16/41 missiles that missed for no reason other than "glint" or a 61% success rate. My question/issue is thus. Is this the intended miss rate for glint. I'm not contesting that glint is an issue for AAM's. I'm positing that this is far far too high an incidence rate of non fuzing misses for missiles that were developed in the 70's and beyond. The declassified Navair 01-245FDB-1T F-4 Phantom Tactical Manual from 1972, lists the expected success rate of an AIM-7E as 85% chance of guiding to within 20 feet (page 1-161 if anybody who has it wants to look). we are currently showing 2-3 times that in failure rate. and that is for the AIM-7E. The AIM-7F has a specified Accuracy of 25 feet according to the SMC documents from 1976 and 1977. Again, if we hold that 85% value, we are still well outside of that. 1972 Navair 01-245FDB-1T page 1-161 SMC 1976 SMC 1977 Why would an AIM-7M do worse than the AIM-7E or AIM-7F is expected to do in this situation. Finally Glint has been a long studied and researched problem. All of these missiles were designed with Glint as a known issue and with it built into the guidance specifications. If you do some research on proposed glint reduction techniques, every single one pre-1960 generally references it as a filtering problem that is too complex due to the number of calculations required. However every single one of those techniques would immediately become a perfect application for the advent of computerized design in the late 60's and early 70's and you can find several references to exactly that happening. Papers about Glint reduction theories https://apps.dtic.mil/sti/pdfs/AD0857647.pdf https://apps.dtic.mil/sti/pdfs/ADA266509.pdf Paper about tracking target centroids that specifically deals with glint https://www.osti.gov/servlets/purl/218705 The other side is that Glint is almost always referenced as a problem resulting in large miss distances for large targets, like bombers, not as much smaller targets like fighters. My position is thus that glint effects are drastically overstated in DCS in the developing API, especially for all missiles that IOC'd in the 1970s. And that especially after 1980 there really should be no effect on the guidance of a missile that puts it outside of fuzing distance due to Glint. If out of those 41 missiles I had fired, 5-6 had missed (an 85% success rate) , I would consider that an acceptable failure rate, and within design specifications. However almost half to a quarter of the missiles just avoiding the target terminally is unacceptable. This level of random miss stacks with all of the other guidance issues missiles have to deal with to get to their target and results in ridiculously ineffective missiles. All 12 of the tracks and all 22 of the Tacviews for my tests are uploaded for anyone to take a look at. I specifically checked each one for end game notching, and for kinematics, there were missiles that pulled 8G's at .9-.85 Mach to make the intercept happen, so if a missile just missed on a 200 foot pass while only pulling 3G's and it had the ability to pull 4-5 more... then that's another problem that needs to get looked at. GlintTracks.7z Glint repeat Tacviews.7z Glint whiffs.7z

In game presently the GBU-24 while it has the model of a BLU-109 bomb body, does not have the weapons effects. It cannot destroy the same targets as a GBU-31v3/4. So as it stands right now in the game, the only thing a GBU-24 has over a GBU-10 is slightly greater range. There is really no reason to take a GBU-24 over a GBU-10 in the game presently. In the video Wags did he mentioned the bump up that the GBU-24 performs. This is also not in the game, and is as can be read from the DTIC paper a key part of all of its flight profiles. Finally the GBU-24 and Paveway 3 system was specifically created as a Low Level LGB, thats one of the key things it was designed to do that the Paveway 2's could not do. As it is right now, if you are at low altitude and you use a Paveway 3, it is exactly the same other than bang bang terminal guidance as a Paveway 2.

I think everyone in here is aware of how bad desync can get thanks. The two issues can definitely compound each other but as always shooters version of the event is all that matters for actually triggering the fuze, This passing through due to high speeds and closure rates vs the frame rate of the game can happen regardless of desync (happens in single player).

The missile flying through the target and then things blowing up later is usually a sign of desync/lag on a multiplayer server not normally a prox fuse issue. That is not necessarily related, but due to the way positions of objects are extrapolated the solutions may be similar.

7E's are already in game. I'm not entirely sure why Heatblur hasn't implemented it, and I have no idea what differentiates it from the AIM-7F in game currently. There were several variants of the AIM-7E, and the Tomcat was only compatible with the AIM-7E-4, the AIM-7E and AIM-7E-2 and AIM-7E-3 were Phantom only. The Iranian Sparrows were either AIM-7E-2's or AIM-7E-3's for their Phantoms IIRC. Either way they weren't originally compatible with the F-14, not that they couldn't have eventually modified them or the AWG-9 to support them. Iranian Tomcats originally were only compatible with AIM-54A's and whatever variant of sidewinder the Iranian's received. Anything else is a later modification.

This used to be an issue with the R-33 before they changed the kinematics and the old AIM-54 before heatblur implemented the F-14 and reworked it. A mach 4 missile would more than half the time just blip through its target based on the frame rate and not fuse when it passed you. Highly unlikely the game can check for collisions any faster than the frame rate but I'd be happy to hear otherwise. Even at 120 FPS that's not going to be a great frame rate for very high speed interactions. The Prox fuse ideally should be based on current and last frame positions plus the line travelled between, and if the aircraft line crossed that line within fuzing distance. Thats my assumption on how you would solve that issue, but I have no idea if ED has implemented something like that or has their own solution.

The AIM-9P was not part of the Tomcat sale to Iran, Aim-9J's and maybe Aim-9E are about the most you could expect just from their F-4D/E's.

Iran was only ever sold Aim-7E's, The AIM-7P was a early to mid 90's upgrade. The Iranian revolution occured 15 years before it was ever in service and Iran never even recieved AIM-7F's........

If you read through the flight profiles in the DTIC article, at a minimum the level flight profile, where it bumps up and then flies level until it acquires the laser spot, would make this an actual Low Level LGB. As of right now that is not a capability that any bomb has in DCS. So yeah it would add functionality and attack options to players.

I am not making assumptions. If you want to take this to PM I'm happy to.